The present invention relates to automated press lines, and more particulary, to an automated press line including presses, each performing a different process, that are connected to each other by a transferring apparatus.
Conventionally, a number of presses, each of which performs a different process, have been arranged along a line and connected to each other by a transferring apparatus to perform a continuous operation.
FIG. 8 shows a typical press line. As shown in FIG. 8, a press line 50 carries out three processes. In process A, which is a press process, a material S is bent. In process B, which is a molding press process, resin is outsert molded to the material S. In process C, which is a cutting press process, molded resin products formed on the material S are cut off. FIGS. 9(a), 9(b), and 9(c) each show the material S after completing processes A, B, and C, respectively.
The press line 50 includes an uncoiler 51. A strip of material S is stamped out into a predetermined shape during a preliminary stamping process and then wound about the uncoiler 51. The material S is fed from the uncoiler 51 by a first gripper feeder 52 to a press 53 to undergo bending (the completion of which is shown in FIG. 9(a)) and then to a molding press 54 to undergo resin molding (the completion of which is shown in FIG. 9(b)).
Afterward, a second gripper feeder 55 feeds the resin-molded material S to a buffer 56, where a buffer dryer 57 dries the resin. The buffer 56 provides the material S with slack, the amount of which is constantly maintained by a loop controller 58.
A third gripper feeder 59 then feeds the material S to a cutting press 60, which cuts out molded products P from the material S at cutting positions X as shown in FIG. 9(c). After the molded products P are cut off, the remaining margins of the material S are lifted away from the cutting position. A lower mold holding the molded products P is moved away from the cutting position so that the molded products P can be retrieved from the lower mold one at a time.
The molded products P are then inspected by an inspecting apparatus 61. A robot hand 62 subsequently carries the molded products to an automatic stocker 63 for storage.
The cycle time of the cutting press 60 differs from that of the molding press 54. Hence, if the material S were fed to the cutting press 60 from the molding press 54 in accordance with the cycle time of the molding press 54, the material S would interfere with the cutting press 60. This would hinder smooth delivery of the material S.
Therefore, the buffer 56 provides the material S with a constant amount of slack between the molding press 54 and the cutting press 60 so that the material S can be fed to the cutting press 60 from the molding press 54 in accordance with the cutting timing of the cutting press 60. However, the buffer 56 lengthens the press line 50.
When starting continuous production on the press line 50, the material S is first fed manually through processes A, B and C. That is, the material S is fed manually during the first cycle. Furthermore, when ending continuous production, the material S in the buffer 56 must be manually fed to the cutting press 60. As a result, the manual operations carried out when starting and ending continuous production prolong the production time.
The third gripper feeder 59 stops feeding the material S when detecting the trailing end of the material S. Thus, molded products P cannot be produced on the portion of the material S located between the third gripper feeder 59 and the pressing location of the cutting press 60. This wastes some of the material S.
Accordingly, it is an objective of the present invention to provide a press line having a shorter length.
To achieve the above objective, the present invention provides a part production line for producing molded parts. The production line includes a plurality of machines arranged in series. Each machine performs a different operation on a continuous strand of material to produce the molded parts. The production line also includes a base and a molding press for molding resin material to sections of the strand in a molding operation cycle. The molding press is mounted on the base. A cutting press separates portions of the strand, which include the resin material, from the strand in a cutting operation cycle. The cutting press is immediately downstream from the molding press and is mounted on the base. A conveyor intermittently transfers the strand along the production line. The conveyor feeds new sections of the strand into the cutting press and the molding press at the same speed and with the same timing.
In a further aspect of the present invention, a method of producing parts is proposed. The method includes intermittently feeding a strand of material through a production line. The production line includes a mold press and a cutting press. The method also includes molding resin material onto portions of the strand with the mold press, and cutting parts, which include the resin, from the strand with the cutting press. The cutting includes moving a die towards an upper tool to clamp the strand between the die and the upper tool and severing the parts from the strand. The method further includes returning the die to a position spaced from the strand after the cutting operation. The severed parts are retained by the die when the die is returned to the spaced position. Furthermore, the method includes moving the die in a direction transverse to the feed direction of the strand to deliver the parts to a retrieval conveyor.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.